Mount Prospect, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

980
FXUS63 KLOT 111056
AFDLOT

Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
556 AM CDT Sat Jul 11 2026

.KEY MESSAGES...

- Isolated to scattered showers and storms around and south of
  US-24 through early this afternoon

- Drier and warmer conditions are expected through early next
  week; cooler near Lake Michigan.

&&

.DISCUSSION...
Issued at 128 AM CDT Sat Jul 11 2026

Showers and storms continue to linger in central Illinois south
of the forecast area, but most of the activity from Ford County
northward has diminished. A 700 mb wave, whose axis is
currently analyzed over the area along a Topeka, KS to Detroit,
MI line, will continue to sink southward through the morning
which will slowly pull the higher moisture content south of the
forecast area as well. Weak forcing from a departing wave
prevents any real concerns for widespread coverage; however,
isolated to scattered showers and storms are still possible
through late morning/early afternoon, most likely around and
south of US-24. Shower and storm chances decrease late afternoon
as the wave finally moves southeast of the area.

Afternoon high temperatures today were lowered by a degree or
two from the previous forecast in large part due to the
extensive cloud cover over the area. While guidance indicates
cloud cover to decreasing through the day as the wave exits,
substantial clearing is not expected until early to mid
afternoon helping to mute temperatures slightly. Additionally,
prevailing northeast winds will help keep cooler temperatures
along the lake shoreline.

Warmer and drier conditions will be the trend over the weekend
into early next week. An amplifying ridge out west will deepen
and tilt northeastward centering the area of high pressure
directly over Chicagoland. 850 mb temperatures are forecasted to
reach 20C by Monday helping to increase high temperatures back
into the 90s. There is a little uncertainty with dew point
temperature trends next week, but heat indices are expected to
max out around the mid 90s. Additionally, there is the potential
for afternoon lake breezes which would help provide some heat
relief near the shoreline.

So how long will the heat last? Most models have the ridge
maintaining its strength through Tuesday and potentially
lingering into Wednesday. After that, models are really
struggling with how the ridge breaks down. There is decent
consensus of a stout upper level low traversing Canada through
next week with the potential of dipping its figurative toes
into the northern Great Lakes mid to late next week which would
bring cooler temperatures and maybe some showers/storms
(depending on its track). However, a few models are suggesting
the very same wave currently over Illinois will sink toward the
Gulf this weekend, pivot slightly early next week, then slowly
work its way northward pulling Gulf moisture with it by mid/late
next week. For now, no changes were made to the chance PoPs the
NBM provided, but there is a lot yet to be determined with how
these system evolve and the potential for cooler air moving in
late next week and into the weekend.

DK

&&

.AVIATION /12Z TAFS THROUGH 18Z SUNDAY/...
Issued at 556 AM CDT Sat Jul 11 2026

There are no significant aviation weather concerns.
Light/variable winds will quickly turn northeasterly and increase
towards 10-15 kts this morning, and some occasional gustiness
towards 20 kts will be possible at times. Winds will ease this
evening before returning out of the NE around 5-10 kts through
Sunday. VFR will prevail with decreasing high cloud cover
through the day.

Carlaw

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.

&&

$$

Visit us at weather.gov/chicago